evalexpr: introduce single op_kind enum

This will allow making the precendence climbing cleaner

src/ast/ast.c

@@ -15,8 +15,12 @@ struct ast_node *make_num(int val)
     return ret;
 }
 
-struct ast_node *make_unop(enum unop_kind op, struct ast_node *tree)
+struct ast_node *make_unop(enum op_kind op, struct ast_node *tree)
 {
+    // Defensive programming
+    if (op >= BINOP_PLUS)
+        return NULL;
+
     struct ast_node *ret = malloc(sizeof(*ret));
 
     if (ret == NULL)
@@ -29,9 +33,13 @@ struct ast_node *make_unop(enum unop_kind op, struct ast_node *tree)
     return ret;
 }
 
-struct ast_node *make_binop(enum binop_kind op, struct ast_node *lhs,
+struct ast_node *make_binop(enum op_kind op, struct ast_node *lhs,
                             struct ast_node *rhs)
 {
+    // Defensive programming
+    if (op < BINOP_PLUS)
+        return NULL;
+
     struct ast_node *ret = malloc(sizeof(*ret));
 
     if (ret == NULL)

src/ast/ast.h

@@ -4,15 +4,14 @@
 // Forward declaration
 struct ast_node;
 
-enum unop_kind
+enum op_kind
 {
+    // Prefix operators
     UNOP_IDENTITY,
     UNOP_NEGATE,
+    // Postfix operators
     UNOP_FACT,
-};
-
-enum binop_kind
-{
+    // Infix operators
     BINOP_PLUS,
     BINOP_MINUS,
     BINOP_TIMES,
@@ -22,13 +21,13 @@ enum binop_kind
 
 struct unop_node
 {
-    enum unop_kind op;
+    enum op_kind op;
     struct ast_node *tree;
 };
 
 struct binop_node
 {
-    enum binop_kind op;
+    enum op_kind op;
     struct ast_node *lhs;
     struct ast_node *rhs;
 };
@@ -51,9 +50,9 @@ struct ast_node
 
 struct ast_node *make_num(int val);
 
-struct ast_node *make_unop(enum unop_kind op, struct ast_node *tree);
+struct ast_node *make_unop(enum op_kind op, struct ast_node *tree);
 
-struct ast_node *make_binop(enum binop_kind op, struct ast_node *lhs,
+struct ast_node *make_binop(enum op_kind op, struct ast_node *lhs,
                             struct ast_node *rhs);
 
 void destroy_ast(struct ast_node *ast);

src/eval/eval.c

@@ -30,8 +30,9 @@ static int eval_unop(const struct unop_node *un_op)
         return -eval_ast(un_op->tree);
     case UNOP_FACT:
         return my_fact(eval_ast(un_op->tree));
-    }
+    default:
         UNREACHABLE();
+    }
 }
 
 static int eval_binop(const struct binop_node *bin_op)
@@ -49,9 +50,10 @@ static int eval_binop(const struct binop_node *bin_op)
         return EVAL_OP(/, bin_op);
     case BINOP_POW:
         return my_pow(eval_ast(bin_op->lhs), eval_ast(bin_op->rhs));
+    default:
+        UNREACHABLE();
     }
 #undef EVAL_OP
-    UNREACHABLE();
 }
 
 int eval_ast(const struct ast_node *ast)

src/parse/climbing_parse.c

@@ -37,7 +37,7 @@ static void skip_whitespace(const char **input)
         eat_char(input);
 }
 
-static enum binop_kind char_to_binop(char c)
+static enum op_kind char_to_binop(char c)
 {
     for (size_t i = 0; i < ARR_SIZE(ops); ++i)
         if (ops[i].fix == OP_INFIX && c == ops[i].op[0])
@@ -46,7 +46,7 @@ static enum binop_kind char_to_binop(char c)
     UNREACHABLE();
 }
 
-static enum unop_kind char_to_unop(char c)
+static enum op_kind char_to_unop(char c)
 {
     for (size_t i = 0; i < ARR_SIZE(ops); ++i)
         if (ops[i].fix != OP_INFIX && c == ops[i].op[0])
@@ -164,7 +164,7 @@ static struct ast_node *climbing_parse_internal(const char **input, int prec)
         eat_char(input);
         if (is_binop(c))
         {
-            enum binop_kind op = char_to_binop(c);
+            enum op_kind op = char_to_binop(c);
             struct ast_node *rhs = climbing_parse_internal(input, right_prec(c));
             if (!rhs)
             {
@@ -227,7 +227,7 @@ static struct ast_node *parse_operand(const char **input)
     int val = 0;
     if (is_prefix(*input[0]))
     {
-        enum unop_kind op = char_to_unop(*input[0]);
+        enum op_kind op = char_to_unop(*input[0]);
         // Remove the parenthesis
         eat_char(input);
 

src/parse/recursive_parse.c

@@ -61,7 +61,7 @@ struct ast_node *recursive_parse(const char *input)
     return ast;
 }
 
-static enum binop_kind char_to_binop(char c)
+static enum op_kind char_to_binop(char c)
 {
     switch (c)
     {
@@ -94,7 +94,7 @@ static struct ast_node *parse_expression(const char **input)
 
         if (*input[0] == '+' || *input[0] == '-')
         {
-            const enum binop_kind op = char_to_binop(*input[0]);
+            const enum op_kind op = char_to_binop(*input[0]);
 
             eat_char(input);
 
@@ -130,7 +130,7 @@ static struct ast_node *parse_term(const char **input)
 
         if (*input[0] == '*' || *input[0] == '/')
         {
-            const enum binop_kind op = char_to_binop(*input[0]);
+            const enum op_kind op = char_to_binop(*input[0]);
 
             eat_char(input);
 
@@ -151,7 +151,7 @@ static struct ast_node *parse_term(const char **input)
     return lhs;
 }
 
-static enum unop_kind char_to_unop(char c)
+static enum op_kind char_to_unop(char c)
 {
     switch (c)
     {
@@ -170,7 +170,7 @@ static struct ast_node *parse_factor(const char **input)
     skip_whitespace(input); // Whitespace is not significant
     while (*input[0] == '+' || *input[0] == '-')
     {
-        const enum unop_kind op = char_to_unop(*input[0]);
+        const enum op_kind op = char_to_unop(*input[0]);
 
         eat_char(input);
 
@@ -197,7 +197,7 @@ static struct ast_node *parse_power(const char **input)
 
     if (*input[0] == '^')
     {
-        const enum binop_kind op = char_to_binop(*input[0]);
+        const enum op_kind op = char_to_binop(*input[0]);
 
         eat_char(input);